The Device Access module contains a set of protocol independent Device Items. The benefits of these items are that there is no need to care about the protocol complexity and to rewrite one and the same application for every protocol or device.

There are three groups of device items:

• Basic Items
• Maintenance Items
• White Goods Items

The group descriptions represent the main idea of every Device Item, its functionality and the operations that can be invoked.

It is very important to provide consistent interface for the devices exposed by the Protocol Adapters . It is also very important to provide the information about the underlying devices in a uniform manner.

Device Item attributes are defined to describe a part or property of the device that cannot be manipulated to serve non standard purposes. For example a temperature sensor cannot be manipulated to measure humidity. Thus it does not make sense to let the user manipulate such information. The function of Device Item attributes is to provide information which the application can use to further determine the functionality of a Functional Item. This information is about, but not limited to:

• The quantity used as in temperature, speed, luminescence and etd;
• The medium measured for example of soil temperature, air relative humidity and so on.
• Type of equipment that a switch operates on.

The Device Item attributes are separated in two groups: General Attributes and Item Specific Attributes. More information about the item specific attributes is available in the corresponding pages about the Device Items.